With the development of the communication technology and the peoples' increasing insight into the trunking system, the trunking system as an efficient emergency command scheduling system plays a more and more important role. A trunking communication system is widely applied in the fields of government departments, public security, emergency communication, electric power, civil aviation, petrochemical industry and military and so on. The development of the trunking system goes through stages of a simulation trunking system and a narrowband digital trunking system, wherein many drawbacks exist in both the two stages of the trunking systems. The simulation trunking system has disadvantages of large interference, many dead zones and limited frequency and so on, and with regard to the narrowband digital trunking system, even though it has improvement on the communication quality and capacity relative to the simulation trunking system, it is still weak in the aspects of data transmission ability and support ability for multimedia services, moreover, the narrowband digital trunking system has certain difficulties in evolving to the LTE-based broadband digital trunking system.
At present, the LTE-based broadband digital trunking system has become a development direction of the next generation trunking system, the studies on the standards related to the LTE-based broadband digital trunking system are being carried out in China, and operators and enterprises wish to complete the deployment of the LTE-based broadband digital trunking system by performing corresponding modifications or extensions based on the current existing LTE network and technology, thus not only the existing LTE network and technology can be well utilized, but also the input costs are minimized for the operators and enterprises at the same time. Therefore, how to utilize the existing LTE network and technology to deploy architecture of the LTE-based broadband digital trunking system and to implement speaking right seizing of trunking services becomes a problem required to be solved urgently.